Melting equipment

ABSTRACT

The melting equipment has a melting furnace that combusts and melts ash, a secondary combustion chamber disposed above the melting furnace, a slag extraction chute that guides slag generated in the melting furnace downward, a bypass channel ( 20 ) that connects the slag extraction chute and the secondary combustion chamber, an ejector ( 22 ) that is provided between the bypass channel ( 20 ), has a contraction portion ( 23 ) at which the channel cross sections are narrowed, and suctions the combustion exhaust gas (G) into the bypass channel ( 20 ), and an adhesion-prevention unit ( 31 ) ( 41 ) that prevent an incorporated substance that incorporates into the combustion exhaust gas (G) from attaching to the inner wall surface ( 21   a ) of the ejector ( 22 ).

FIELD OF THE INVENTION

The present invention relates to a melting equipment.

Priority is claimed on Japanese Patent Application No. 2010-134194,filed on Jun. 11, 2010, the entire content of which is incorporatedherein by reference.

DESCRIPTION OF RELATED ART

As is well known, there is a gasification melting system as a techniquethat can treat a wide range of wastes from municipal waste tonon-flammable waste, burned residues, sludge, landfilled solid waste,and the like. The gasification melting system is provided with: agasification furnace that thermally decomposes and thus gasifies waste;and a melting equipment that is arranged on the downstream side of thegasification furnace and combusts the thermally decomposed gas generatedfrom the gasification furnace at a high temperature so as to melt ash inthe gas into molten sludge.

The following Patent Document 1 discloses a gasification melting systemequipment provided with: a melting furnace that combusts thermallydecomposed gas and chars at a high temperature; an exhaust equipmentthat exhausts slag generated from the melting furnace; and a secondarycombustion chamber that combusts the combustion exhaust gas generatedfrom the melting furnace a second time. The gasification melting systemequipment is provided with: an ejector that suctions the combustionexhaust gas through a combustion exhaust gas extraction pipe that isprovided at the bottom portion of a slag tap of the melting furnace; anda fan that sends driving air to the ejector for suctioning thecombustion exhaust gas into the ejector. With the above configuration,the high-temperature combustion exhaust gas is circulated so as tomaintain the slag tap at a high temperature, thereby continuouslysuppressing solidification of slag and continuing favorable circulationwithout lowering the temperature of the combustion exhaust gas forcirculation.

PRIOR ART DOCUMENT [Patent Document]

-   [Patent Document 1] Japanese Unexamined Patent Application, First    Publication No. 2003-161411

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, in the related art, there was a problem in that the circulationof the combustion exhaust gas becomes unstable because salts having alow melting temperature and/or slag droplets and the like that areaccompanied by the combustion exhaust gas are incorporated into thecombustion exhaust gas, move along with the combustion exhaust gas, andcause the incorporated substance to attach to the inner wall surface ofthe ejector.

The present invention has been made in consideration of the abovecircumstance, and an object thereof is to provide a melting equipmentthat can stably circulate combustion exhaust gas by suppressing cloggingor narrowing a channel of the combustion exhaust gas.

Means for Solving the Problem

In order to achieve the above object, the present invention employs thefollowing measures.

That is, according to a first aspect of the present invention, agasification melting furnace is provided with: a melting furnace thatcombusts and melts ash; a secondary combustion chamber disposed abovethe melting furnace; a slag extraction chute that guides slag generatedin the melting furnace downward; a bypass channel that connects the slagextraction chute and the secondary combustion chamber; an ejector thatis provided on the bypass channel, has a contraction portion at which achannel cross section thereof is narrowed, and suctions the combustionexhaust gas into the bypass channel; and an adhesion-prevention unitthat prevents an incorporated substance that is incorporated in thecombustion exhaust gas from attaching to the inner wall surface of theejector.

According to the above configuration, since the adhesion-prevention unitis included, an incorporated substance of dust or salts in thecombustion exhaust gas is prevented from attaching to the inner wallsurface of the ejector. Thereby, the combustion exhaust gas channel isnot clogged or narrowed; and therefore the combustion exhaust gas can bestably circulated.

In addition, the adhesion-prevention unit preferably has an adheredsubstance removal portion that removes an adhered substance that isattached to the inner wall surface of the ejector.

According to the above configuration, since the adhered substanceremoval portion that removes the adhered substance that is attached tothe inner wall surface of the ejector is included, the adhered substancecan be removed even when the incorporated substance included in thecombustion exhaust gas is attached to the inner wall surface of theejector.

In addition, the adhered substance removal portion preferably suppliesvibration to the inner wall surface of the ejector.

According to the above configuration, since the adhered substanceremoval portion supplies vibration to the inner wall surface of theejector, the adhered substance on the inner wall surface of the ejectorcan be removed without inhibiting the smooth flow of the combustionexhaust gas or driving air of the ejector.

In addition, the adhered substance removal portion preferably blows airto the inner wall surface of the ejector.

According to the above configuration, since the adhered substanceremoval portion blows air to the inner wall surface of the ejector, itis possible to remove the adhered substance being attached to the innerwall surface of the ejector using blown air, and join the removedadhered substance into the flow of the ejector. Thereby, the adheredsubstance can be blown toward the downstream side more reliably, andefforts for maintenance, such as cleaning, can be reduced.

In addition, the adhered substance removal portion preferably performsmechanical washing on the inner wall surface of the ejector.

According to the configuration, since the adhered substance removalportion performs mechanical washing on the inner wall surface of theejector, the adhered substance on the inner wall surface of the ejectorcan be directly removed.

In addition, the adhesion-prevention unit preferably has a swirlingseparation portion that is provided upstream of the contraction portion,swirls the introduced combustion exhaust gas so as to form a swirlingflow, and centrifugally separates any incorporated substance included inthe swirling flow.

According to the above configuration, since the swirling separationportion that centrifugally separates the incorporated substance includedin the swirling flow is included upstream of the contraction portion, anincorporated substance that reaches the contraction portion can bereduced. Thereby, the adhered substance that is attached to the innerwall surface of the ejector can be reduced.

In addition, the swirling separation portion preferably has a coolingsystem that cools the inner wall along which the swirling flow of thecombustion exhaust gas flows.

According to the above configuration, since the cooling system thatcools the inner wall along which the swirling flow of the combustionexhaust gas flows is included, it is possible to separate saltsincorporated in the combustion exhaust gas and the combustion exhaustgas by solidifying the volatilized salts that are included in thecombustion exhaust gas. Thereby, the adhered substance that is attachedto the inner wall surface of the ejector can be further reduced.

In addition, a plurality of the ejectors is preferably provided in arow.

According to the above configuration, since the plurality of theejectors is provided in a row, the combustion exhaust gas can befavorably introduced to the bypass channel even when the swirlingseparation portion having a great pressure loss is provided at upstreamof the contraction portion.

In addition, the adhesion-prevention unit preferably has an air filmforming portion that forms an air film along the inner wall surface ofthe ejector.

According to the above configuration, since the air film forming portionthat forms an air film along the inner wall surface of the ejector isincluded, the incorporated substance included in the combustion exhaustgas does not easily reach the inner wall surface of the ejector.Thereby, the incorporated substance that is attached to the contractionportion can be reduced.

In addition, the adhesion-prevention unit preferably has a plurality ofreplaceable branching channels that is provided at the bypass channel,and branches on the upstream side and joins with the downstream side,and each of the plurality of the branching channels has an ejector.

According to the above configuration, since the bypass channel has aplurality of the replaceable branching channels that branches on theupstream side, and joins with the downstream side, and the ejector isprovided at each of the branching channels, it is possible to circulatethe combustion exhaust gas using one branching channel and to clean theejector in the other branching channel. Therefore, it is possible toclean the ejector so as to remove the adhered substance on the innerside surface of the ejector while continuing the operation of themelting equipment.

In addition, the adhesion-prevention unit preferably has a liquiddispersion portion that is provided at upstream of the ejector, anddisperses liquid in the combustion exhaust gas so as to remove theincorporated substance included in the combustion exhaust gas, and thedriving air in the ejector preferably has a temperature that is equal toor higher than the temperature at which the dispersed liquid gasifies.

According to the above configuration, since the adhesion-prevention unithas the liquid dispersion portion, and the driving air in the ejectorhas a temperature that is equal to or higher than the temperature atwhich the dispersed liquid gasifies, even when liquid mist is includedin the combustion exhaust gas through liquid dispersion, the liquid isgasified so as to suppress the liquid being attached to the inner wallsurfaces of the ejectors and the wall surfaces of the bypass channel.Thereby, trapping of the residual incorporated substance in thecombustion exhaust gas by the liquid attached to the inner wall surfacesof the ejectors and the wall surfaces of the bypass channel issuppressed; and therefore the combustion exhaust gas channel isprevented from being clogged or narrowed, whereby the combustion exhaustgas can be stably circulated.

Effects of the Invention

According to the melting equipment of the present invention, it ispossible to stably circulate combustion exhaust gas by suppressingclogging or narrowing of the channel of combustion exhaust gas.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a gasification melting system S accordingto an embodiment of the present invention.

FIG. 2 is an enlarged view of the main parts of melting equipment 1Aaccording to a first embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of an ejector 21 according tothe first embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of an ejector 21A accordingto a first modified example of the first embodiment of the presentinvention.

FIG. 5 is an enlarged cross-sectional view of an ejector 21B accordingto a second modified example of the first embodiment of the presentinvention.

FIG. 6 is an enlarged view of the main parts of melting equipment 1Baccording to a second embodiment of the present invention.

FIG. 7 is a schematic configuration view of melting equipment 1B1according to a first modified example of the second embodiment of thepresent invention.

FIG. 8 is an enlarged cross-sectional view of the main parts of meltingequipment 1B2 according to a second modified example of the secondembodiment of the present invention.

FIG. 9 is an enlarged cross-sectional view of the main parts of meltingequipment 1C according to a third embodiment of the present invention.

FIG. 10 is a schematic configuration view showing an adhesion-preventionunit 36A according to a modified example of the third embodiment of thepresent invention.

FIG. 11 is a schematic configuration view showing melting equipment 1Daccording to a fourth embodiment of the present invention.

FIG. 12 is a schematic configuration view showing melting equipment 1Eaccording to a fifth embodiment of the present invention.

EMBODIMENTS OF THE INVENTION

Hereinafter, embodiments of the present invention will be described withreference to the accompanying drawings.

Firstly, a gasification melting system according to first to fourthembodiments of the present invention will be schematically described.

(Gasification Melting System)

FIG. 1 is a schematic view of a gasification melting system S.

The gasification melting system S is provided with: a fluidized-bed typegasification furnace 100 that thermally decomposes and gasifies waste; amelting equipment 1A that is provided on the downstream side of thefluidized-bed type gasification furnace 100, and combusts thermallydecomposed gas C generated in the fluidized-bed type gasificationfurnace 100 at a high temperature so as to make ash in the gas intomolten slag; and an exhaust gas treatment equipment 200 that treatscombustion exhaust gas G exhausted from the melting equipment 1A.

The fluidized-bed type gasification furnace 100 includes: a wasteinjection hopper 101 through which waste D is injected; a pusher-typefirst refuse feeding apparatus 102 a that has an inlet connected to theoutlet of the waste injection hopper 101, and pushes out the waste D inthe horizontal direction; a connection chute 102 b that is connected tothe outlet of the first refuse feeding apparatus 102 a at the topportion, and forms a vertically extending space; a screw-type secondrefuse feeding apparatus 102 c having an inlet connected to the bottomportion of the connection chute 102 b; and a furnace main body 103 towhich a fixed amount of the waste D is supplied from the second refusefeeding apparatus 102 c.

Combustion air B1 having, for example, a temperature of approximately120° C. to 230° C. and an air ratio of approximately 0.2 to 0.7 is blowninto the furnace main body 103 through a wind box 103 a from the furnacebottom portion, and the fluidized layer temperature is maintained atapproximately 450° C. to 600° C. The furnace main body 103 turns thewaste D into thermally decomposed gas so as to decompose the waste Dinto gas, gaseous tar and char (carbides). An incombustible substance Nis sequentially exhausted from an incombustible substance exhaustopening 103 b.

Char is gradually pulverized in the fluidized layer of the furnace mainbody 103, and is introduced to a swirling melting furnace 2 of themelting equipment 1A in conjunction with the gas and gaseous tar.Hereinafter, the components that are introduced to the swirling meltingfurnace 2 will be collectively referred to as thermally decomposed gasC.

(Melting Equipment)

FIG. 2 is an enlarged view of the main parts of melting equipment 1A.

As shown in FIG. 2, the melting equipment 1A is provided with: thevertical swirling melting furnace (melting furnace) 2; a secondarycombustion chamber 8 disposed above the swirling melting furnace 2; aslag extraction chute 7 that has a slag cut burner 7 a and guides slaggenerated in the swirling melting furnace 2 downward; a boiler 9disposed on the downstream side of the secondary combustion chamber 8; agranulation tank 10 provided below the swirling melting furnace 2; and abypass channel 20 connecting the slag extraction chute 7 and thesecondary combustion chamber 8.

As shown in FIGS. 1 and 2, the swirling melting furnace 2 includes athermal decomposition gas burner 3 that mixes the thermally decomposedgas C exhausted from the fluidized-bed type gasification furnace 100with combustion air B2 and blows the gas mixture into the furnace.

In the swirling melting furnace 2, as shown in FIG. 2, the gas mixtureof the thermally decomposed gas C and the combustion air B2 is combustedwhile forming a swirling flow so that the temperature inside the furnaceis maintained at 1300° C. to 1500° C., and ash in the thermallydecomposed gas C is melted and made into slag. The molten slag isattached to the inner wall surface of the swirling melting furnace 2,flows downward, and is exhausted into the granulation tank 10 throughthe slag extraction chute 7 from a slag cinder notch 6 at the furnacebottom portion.

The bypass channel 20, as shown in FIG. 2, has an ejector 21 that isprovided on the way of the bypass channel 20 and suctions the combustionexhaust gas G, and is configured to guide the combustion exhaust gas Gto the secondary combustion chamber 8 from the slag extraction chute 7through the bypass channel 20. That is, the high-temperature combustionexhaust gas G continuously passes through the slag cinder notch 6 sothat solidification of the molten slag is suppressed. The details of thebypass channel 20 will be described below in detail.

As shown in FIG. 1, the slag exhausted to the granulation tank 10 israpidly cooled in the granulation tank 10, transported out through aslag conveyer 10 a, and collected as granulated slag. The collectedgranulated slag can be effectively used as roadbed material and thelike.

On the other hand, the combustion exhaust gas G exhausted from theswirling melting furnace 2 is introduced to the secondary combustionchamber 8 through a connection portion 5. The secondary combustionchamber 8 combusts uncombusted components in the combustion exhaust gasG using supplied combustion air B3. After that, the combustion exhaustgas G is thermally collected in the boiler 9, cooled to approximately200° C. to 250° C., and sent to the exhaust gas treatment equipment 200.

Returning to FIG. 1, in the exhaust gas treatment equipment 200, thecombustion exhaust gas G exhausted from the boiler 9 is introduced to atemperature reduction tower 201, cooled to approximately 150° C. to 180°C. by spraying water directly, then, sprayed lime hydrate and activatedchar in a smoke path according to necessity, and introduced to areaction dust collection apparatus 202.

In addition, in the reaction dust collection apparatus 202, smoke dust,acidic gas, DXNs and the like in the combustion exhaust gas G areremoved, and then dust ash exhausted from the reaction dust collectionapparatus 202 is treated by a chemical treatment and is landfilled. Thecombustion exhaust gas G from which smoke dust, acidic gas, DXNs and thelike are removed is reheated in a steam heater 203, and NO_(x) isremoved in a catalyst reaction apparatus 204, and then, the combustionexhaust gas is emitted in the air through a chimney pipe 206 through aninduction fan 205.

(Ejector)

FIG. 3 is an enlarged cross-sectional view of the ejector 21.

As shown in FIG. 3, the ejector 21 is provided with: a cylinder portion22 which has a cylindrical shape and a closed bottom, and is connectedto the bypass channel 20 through which the combustion exhaust gas Gflows; a contraction portion 23 in which the channel cross sectionthereof become narrowed while extending toward the downstream side ofthe cylinder portion 22; a radially expanding portion 24 that iscontinuously provided to the downstream side of the contraction portion23; and a driving air supply pipe 25 that is coaxially provided with thecylinder portion 22 and ejects high-pressure air A toward the downstreamside from the front end opening portion surrounded by the contractionportion 23.

The contraction portion 23 includes: a tapering portion 23 a having adiameter gradually contracting from the upstream of the channel towardthe downstream; and a small diameter portion 23 b that continues to thedownstream side of the tapering portion 23 a and has a substantiallyconstant diameter.

In the ejector 21, when the high-pressure air A is injected from thedriving air supply pipe 25, the flow velocity of the high-pressure air Ais increased through the contraction portion 23. The high-pressure air Ahaving an increased flow velocity entrains and flows the ambientcombustion exhaust gas G toward the downstream, and thus turns theupstream side of the ejector 21 into a negative pressure. Thereby, thecombustion exhaust gas G is suctioned from the slag extraction chute 7(refer to FIG. 2). Meanwhile, the position of the ejector 21 may beappropriately changed, and the flow direction of the high-pressure air Aor the introduction direction of the combustion exhaust gas G can alsobe appropriately set.

(Adhesion-Prevention Unit) (Adhered Substance Removal Portion)

As shown in FIG. 3, the ejector 21 having the above configuration isprovided with an adhesion-prevention unit 31 that prevents adhesion ofan incorporated substance that incorporates into the combustion exhaustgas G. The adhesion-prevention unit 31 has an air knocker (adheredsubstance removal portion) 41 that removes an adhered substance F thatis attached to the inner wall surface 21 a of the ejector 21.

As shown in FIG. 3, the air knocker 41 is disposed so as to strike theouter wall surface of the tapering portion 23 a on the small diameterportion 23 b side and thus supply vibration to the inner wall surface 21a of the ejector 21. The air knocker 41 does not operate at all times,but operates on a regular basis.

Next, the operations of the adhesion-prevention unit 31 and the airknocker 41 having the above configurations will be described.

When the ejector 21 is driven in a state in which the air knocker 41 isnot in operation, the combustion exhaust gas G flows through the bypasschannel 20 from the slag extraction chute 7 toward the secondarycombustion chamber 8 as shown in FIG. 2 due to the above action. In theejector 21, the combustion exhaust gas G repeatedly collides with theinner wall surface 21 a of the contraction portion 23 such that amixture that is entrained with the combustion exhaust gas G is attachedto and accumulated on the inner wall surface 21 a, and thus the adheredsubstance F grows.

The adhered substance F that is attached to and accumulated on the innerwall surface 21 a is composed of dust or salts that are included in thecombustion exhaust gas G, and the major components are CaCl₂, CaSO₄,NaCl, Na₂SO₄, KCl, K₂SO₄, SiO₂, and Al₂O₃.

When a predetermined time elapses, the air knocker 41 comes intooperation. The air knocker 41 strikes the outer wall surface of theejector 21, and supplies vibration to the inner wall surface 21 a of theejector 21. The adhered substance F that is attached to the inner wallsurface 21 a is fallen off by the vibration. The adhered substance Fthat is fallen off from the inner wall surface 21 a is entrained andflew by the high-pressure air A and the combustion exhaust gas G towardthe downstream side, made to flow through the bypass channel 20, finallyreaches the secondary combustion chamber 8, and is combusted.Alternatively, the adhered substance accumulates on the bottom portionof the ejector 21. The accumulated substance in the ejector 21 isexhausted outside the ejector 21 from a cleaning opening, not shown, byregular cleanings.

In addition, the air knocker 41 operates for a certain time, and then,again, comes into stop.

In the ejector 21 in which the adhered substance F is removed asdescribed above, the combustion exhaust gas G channel is neither cloggednor narrowed, and the combustion exhaust gas G stably circulates.

As described above, since the melting equipment 1A includes theadhesion-prevention unit 31, adhesion of the incorporated substance thatincorporates into the combustion exhaust gas G (dust, salts, or thelike) to the inner wall surface 21 of the ejector 21 is prevented.Thereby, the combustion exhaust gas G channel is prevented from beingclogged or narrowed, and therefore the combustion exhaust gas G iscapable of being stably circulated.

In addition, since the air knocker 41 is included, the adhered substanceF is removed even when the incorporated substance in the combustionexhaust gas G is attached to the inner wall surface 21 a of the ejector21. Thereby, the channel of the combustion exhaust gas G being cloggedor narrowed is suppressed so that the combustion exhaust gas G iscapable of being stably circulated.

In addition, since the air knocker 41 supplies vibration to the innerwall surface 21 a of the ejector 21, the adhered substance F on theinner wall surface 21 a of the ejector 21 is capable of being removedwithout inhibiting the smooth flow of the combustion exhaust gas G orthe high-pressure air A in the ejector 21. Furthermore, theconfiguration of the apparatus becomes simple.

In the above configuration, the number of the air knocker 41 used issingle, but may be plural. In a case in which a plurality of the airknockers 41 is used, when the air knockers are provided at substantiallyequal intervals in the circumferential direction of the gas channelcross section, vibration is capable of being evenly supplied to theinner wall surface 21 a, and the adhered substance F locally remainingon the inner wall surface 21 a of the ejector 21 can be suppressed.

In addition, in the above configuration, the air knocker 41 is used, butthe ejector may be driven by oil pressure, or vibration may be suppliedby a motor as long as vibration can be supplied to the inner wallsurface 21 a of the ejector 21.

In addition, in the above configuration, the air knocker 41 is operatedon a regular basis, but may be operated at all times.

In addition, the frequencies of vibration supplied to the inner wallsurface 21 a may be changed by changing timings at which the air knocker41 strikes the outer wall surface.

First Modified Example of the First Embodiment

FIG. 4 is an enlarged cross-sectional view of an ejector 21A accordingto a first modified example of the first embodiment.

As shown in FIG. 4, an adhesion-prevention unit 32 is provided with theejector 21A. The adhesion-prevention unit 32 has an air bluster (adheredsubstance removal portion) 42 that removes the adhered substance F thatis attached to the inner wall surface 21 a of the ejector 21A.

The air bluster 42 is formed into a long shape, and compressed air a isinjected from a front end portion 42 a. The air bluster 42 extendssubstantially along the driving air supply pipe 25 from an end wall 21 bof the ejector 21A (cylinder portion 22) to the vicinity of thecontraction portion 23 (tapering portion 23 a).

The end wall 21 b of the ejector 21A has a dual structure. The end wall21 b is configured to overlap an inner end wall 21 c having a circularhole 21 e formed therein and an outer end wall 21 d that is provided soas to be rotatable with respect to the inner end wall 21 c, and sealsthe ejector 21A air-tightly.

The air bluster 42 is movably inserted to the circular hole 21 e of theinner end wall 21 c so as to be rotatable in the circumferentialdirection of the channel cross section. In addition, the air bluster 42penetrates the outer end wall 21 d in a state in which the air tightnesswith the outer end wall 21 d is secured, is refrained so as to berelatively rotating with respect to the outer end wall 21 d, and iscapable of being relatively moved in the tube axial direction of thecylinder portion 22.

The above configuration enables the front end portion 42 a of the airbluster 42 to face the contraction portion 23 of the ejector 21Athroughout the entire circumstance and to stay ready at the bottom whilenot in operation.

According to the air bluster 42, since the compressed air a is blown tothe inner wall surface 21 a of the ejector 21A, the removed adheredsubstance F is capable of being rapidly joined into the flow of thehigh-pressure air A that is injected by the ejector 21A. Thereby, theadhered substance F is capable of being blown more reliably into thesecondary combustion chamber 8 on the downstream side. Furthermore, theadhered substance F that falls and remains on the end wall 21 b iscapable of being decreased, and it is possible to reduce efforts formaintenance, such as cleaning.

In addition, since the air bluster is capable of being rotatedsubstantially the entire circumference in the circumferential directionin the channel cross section of the contraction portion 23 of theejector 21A, the adhered substance F that is attached to the inner wallsurface 21 a of the contraction portion 23 is capable of being removedthroughout the entire circumference in the circumferential direction inthe channel cross section without remainder. In addition, since only oneair bluster 42 is provided, the space factor of the ejector 21A can beimproved.

Second Modified Example of the First Embodiment

FIG. 5 is an enlarged cross-sectional view of an ejector 21B accordingto a second modified example of the first embodiment.

As shown in FIG. 5, the ejector 21B is provided with anadhesion-prevention unit 33. The adhesion-prevention unit 33 includes awashing brush (adhered substance removal portion) 43 that removes theadhered substance F that is attached to the inner wall surface 21 a ofthe ejector 21B.

The washing brush 43 is formed into a long shape, and has a number ofwashing bristles at a front end portion 43 a. The washing brush 43extends substantially along the driving air supply pipe 25 from the endwall 21 b of the ejector 21 to the vicinity of the contraction portion23.

Similarly to the air bluster 42, the washing brush 43 is configured soas to be rotatable in the circumferential direction of the channel crosssection and movable in the tube axial direction of the cylinder portion22. The washing brush 43 stays ready at the bottom while not inoperation, and moves the front end portion 43 a toward the contractionportion 23 side so as to bring the washing bristles into contact withthe adhered substance F while in operation. In addition, the washingbrush 43 rotates in the circumferential direction of the channel crosssection while advancing and retreating in the tube axial direction ofthe cylinder portion 22 so as to mechanically wash the adhered substanceF.

According to the above configuration, since the washing brush 43mechanically washes the inner wall surface 21 a of the ejector 21, theadhered substance F on the inner wall surface 21 a of the ejector 21 canbe directly removed, and even strongly fixed adhered substance F can beremoved more reliably.

In the above configuration, the air bluster 42 and the washing brush 43are rotated, but may remain still.

In the above configuration, the numbers of the air bluster 42 and thewashing brush 43 that are provided are single, but may be plural.

In addition, in the above configuration, the air bluster 42 and thewashing brush 43 are provided, but may be provided together or in anoverlapping manner the air knocker 41.

In addition, in the above configuration, the air bluster 42 and thewashing brush 43 are configured to be automatically operated, but may beoperated manually so as to remove the adhered substance F.

Second Embodiment

FIG. 6 is an enlarged view of the main parts of melting equipment 1Baccording to a second embodiment of the invention.

In FIG. 6, the same configuration components as in FIGS. 1 to 5 will begiven to the same reference signs, and a description thereof will not bemade.

As shown in FIG. 6, the melting equipment 1B includes anadhesion-prevention unit 34. The adhesion-prevention unit 34 includes acyclone separator (swirling separation portion) 44 provided upstream ofthe ejector 21 in the bypass channel 20. The cyclone separator 44 swirlsthe introduced combustion exhaust gas G so as to form a swirling flow,and centrifugally separates an incorporated substance included in theswirling flow. The cyclone separator 44 includes a cooling system 44 bthat cools an inner wall 44 a along which the swirling flow of thecombustion exhaust gas G flows. The cooling system 44 b cools thetemperature of the inner wall 44 a to the solidification point or lowerof volatile salts (volatilized salts) included in the combustion exhaustgas G.

Next, the operations of the adhesion-prevention unit 34 and the cycloneseparator 44 having the above configuration will be described.

When the combustion exhaust gas G is suctioned into the bypass channel20 due to a negative pressure, the combustion exhaust gas G is guided tothe cyclone separator 44. The cyclone separator 44 forms a swirling flowby flowing the combustion exhaust gas G along the inner wall 44 a. Inaddition, the incorporated substance included in the combustion exhaustgas G is centrifugally separated, and guided downward while theincorporated substance collides with the inner wall 44 a and moves in aswirling form.

At this time, since the inner wall 44 a is cooled to a temperature thatis equal to or lower than the solidification point of the salts includedin the combustion exhaust gas G, the volatile salts in the combustionexhaust gas G are solidified, and guided downward in the same manner asabove.

The combustion exhaust gas G from which the incorporated substance andthe volatile salts are removed is exhausted from the cyclone separator44 and guided to the ejector 21. The combustion exhaust gas G introducedto the ejector 21 is entrained by the high-pressure air A injected fromthe driving air supply pipe 25 and is flowed toward the downstream sidealong the inner wall surface 21 a of the contraction portion 23;however, the incorporated substance and the volatile salts have beenremoved, the adhered substance F is not easily attached to the innerwall surface 21 a of the contraction portion 23.

As described above, since the cyclone separator 44 that centrifugallyseparates the incorporated substance included in the swirling flow isincluded upstream of the contraction portion 23 of the ejector 21, it ispossible to reduce the incorporated substance being reached thecontraction portion 23. Thereby, the adhered substance F that isattached to the contraction portion 23 of the ejector 21 (refer to FIG.3) can be reduced.

In addition, since the inner wall 44 a of the cyclone separator 44 iscooled, the volatile salts included in the combustion exhaust gas G iscapable of being solidified and separated. Thereby, the adheredsubstance F that is attached to the inner wall surface 21 a of thecontraction portion 23 of the ejector 21 can be further reduced.

Even in the above configuration, when the melting equipment 1B isoperated for a long time, there is a possibility of the adheredsubstance F being generated on the inner wall surface 21 a of thecontraction portion 23 of the ejector 21. When the adhesion-preventionunit 34 is configured by adding at least one of the air knocker 41, theair bluster 42, and the washing brush 43 in the first embodimenttogether with the cyclone separator 44 in order to remove the adheredsubstance F, the combustion exhaust gas G channel is capable of beingmore reliably prevented from being clogged or narrowed, and thecombustion exhaust gas G can be more stably circulated.

First Modified Example of the Second Embodiment

FIG. 7 is a schematic configuration view of melting equipment 1B1according to a first modified example of the second embodiment.

In the above described melting equipment 1B, a single ejector 21provided at the downstream of the cyclone separator 44, but the meltingequipment 1B1 is provided with a plurality of the ejectors 21 in a rowas shown in FIG. 7.

According to the above configuration, since two ejectors 21 are providedin a row, in a case in which the cyclone separator 44 having a largepressure loss is provided, a greater negative pressure is capable ofbeing exerted on the downstream side of the cyclone separator 44, andthe combustion exhaust engine G is capable of being favorably guided tothe bypass channel 20 even when the gas flow velocity that is set in theejector 21 cannot be increased.

It is needless to say that three or more ejectors 21 may be provided ina row.

Second Modified Example of the Second Embodiment

FIG. 8 is an enlarged cross-sectional view of the main parts of meltingequipment 1B2 according to a second modified example of the secondembodiment.

As shown in FIG. 8, the melting equipment 1B2 includes anadhesion-prevention unit 35. The adhesion-prevention unit 35 has aswirling separation cylinder (swirling separation portion) 22 x thatconsists a part of an ejector 26.

The ejector 26 is provided instead of the ejector 21. The ejector 26 notonly includes the contraction portion 23 and the radially expandingportion 24, but also has the swirling separation cylinder (swirlingseparation portion) 22 x disposed in a portion corresponding to thecylinder portion 22 in the ejector 21.

The swirling separation cylinder 22 x has the cylinder axis in thesubstantially vertical direction. The swirling separation cylinder 22 xis schematically consisted of a fixed diameter portion 26 a that isformed in a substantially fixed diameter and has an introduction opening26 f through which the combustion exhaust gas G is introduced from thetangential direction, formed therein, a taper portion 26 b thatcontinues to the bottom of the fixed diameter portion 26 a and has adiameter gradually contracting downward. The swirling separationcylinder 22 x further includes an inner circumferential partition 26 ddropping from the entire circumference of the edge portion of a gasoutlet 26 c that opens at the top portion of the fixed diameter portion26 a, and an incorporated substance exhausting portion 26 e formed atthe lower end of the taper portion 26 b.

In addition, the ejector is configured that the contraction portion 23disposed on the top of the gas outlet 26 c and the driving air supplypipe 25 penetrates through the gas outlet 26 c and the incorporatedsubstance exhausting portion 26 e.

That is, when the combustion exhaust gas G is introduced from theintroduction opening 26 f, the combustion exhaust gas G flows along theinner circumferential wall of the fixed diameter portion 26 a so thatthe swirling flow of the combustion exhaust gas G is formed, and theincorporated substance included in the combustion exhaust gas G iscentrifugally separated. The centrifugally separated incorporatedsubstance collides with the inner wall 44 a of the taper portion 26 b soas to be guided downward while moving in a swirling shape, and isexhausted from the incorporated substance exhausting portion 26 e(indicated by reference sign fin FIG. 8). On the other hand, thecombustion exhaust gas G from which the incorporated substance isseparated is exhausted from the gas outlet 26 c on the top. At thistime, since the inner circumferential partition 26 d preventsinterruption between the combustion exhaust gas G exhausted from the gasoutlet 26 and the combustion exhaust gas G introduced from theintroduction opening 26 f, it is possible to suppress that theincorporated substance included in the combustion exhaust gas G that isnewly introduced from the introduction opening 26 f is exhausted fromthe gas outlet 26 c.

In the above manner, the combustion exhaust gas G exhausted from the gasoutlet 26 c is wound by the high-pressure air that is injected from thedriving air supply pipe 25 and is flowed to the downstream side.

Even in this case, since the incorporated substance of the combustionexhaust gas G is removed, the adhered substance F is not easilygenerated on the inner wall surface 21 a of the contraction portion 23in the ejector 26, and the same effect as the above effect can beobtained.

The adhesion-prevention unit 35 may be configured by providing thecyclone separator 44, the air knocker 41, the air buster 42, and thewashing brush 43 in addition the ejector 26. The air blaster 42 and thewashing brush 43 may be provided at locations at which the fixeddiameter portion 26 a and the like are not interrupted. In addition,similarly to the above described cyclone separator 44, theadhesion-prevention unit may be configured to cool the fixed diameterportion 26 a and the inner circumferential wall of the taper portion 26b.

Third Embodiment

FIG. 9 is an enlarged cross-sectional view of the principal parts ofmelting equipment 1C according to a third embodiment of the invention.Meanwhile, in FIG. 9, the same configuration components as in FIGS. 1 to8 will be given the same reference signs, and description thereof willnot be made.

As shown in FIG. 9, the melting equipment 1C has almost the sameconfiguration as the melting equipment 1A, but there is a difference inthat an ejector 27 is provided instead of the ejector 21. The ejector 27is provided with an adhesion-prevention unit 36. The adhesion-preventionunit 36 has a plurality of air supply pipes (air film forming portion)45.

The air supply pipe 45 opens the beginning end of the contractionportion 23 on the upstream side, ejects air s, and forms an air filmalong the inner wall surface 21 a of the ejector 27. That is, when theair s is supplied from the air supply pipe 45, the air s is absorbedinto the flows of the combustion exhaust gas G and the high-pressure airA, and an air film that flows toward the downstream side along the innerwall surface 21 a is formed.

Thereby, the incorporated substance included in the combustion exhaustgas G does not easily reach the inner wall surface 21 a of the ejector27. Thereby, the adhered substance that is attached to the contractionportion 23 is capable of being reduced.

Modification Example of the Third Embodiment

FIG. 10 is a schematic configuration view showing an adhesion-preventionunit 36A according to a modified example of the third embodiment of theinvention.

As shown in FIG. 10, the adhesion-prevention unit 36A includes a drivingair supply pipe (air film forming portion) 46 that forms an air filmalong the inner wall surface 21 a of the ejector 28.

The driving air supply pipe 46 supplies the high-pressure air A as thedriving air of the ejector 28. That is, in the ejector 28, the drivingair supply pipe 46 that introduces the high-pressure air A as thedriving air to the cylinder portion 22 is opened, the bypass channel 20that introduces the combustion exhaust gas G is penetrated through thecylinder portion 22, and includes the front end opening portionsurrounded by the contraction portion 23. The ejector has a reverseposition relationship with respect to the driving air supply pipe 25 andthe bypass channel 20 of the above described ejector 21.

According to the adhesion-prevention unit 36A, the high-pressure air Aflows along the inner wall surface 21 a of the ejector 28 and forms anair film, and the combustion exhaust gas G flows toward the downstreamside from the bypass channel 20 in a state of being surrounded by theair film. Thereby, the incorporated substance included in the combustionexhaust gas G does not easily reach the inner wall surface 21 a of theejector 28. As a result, it is possible to reduce the incorporatedsubstance being attached to the contraction portion 23 of the ejector28.

Fourth Embodiment

FIG. 11 is a schematic configuration view showing melting equipment 1Daccording to a fourth embodiment of the invention. In FIG. 11, the sameconfiguration components as in FIGS. 1 to 10 will be given the samereference signs, and description thereof will not be made.

As shown in FIG. 11, the melting equipment 1D includes anadhesion-prevention unit 37. The adhesion-prevention unit 37 has twobranching channels 62A and 62B that are provided in series in a bypasschannel 62.

The two branching channels 62A and 62B branch at a branching portion 62a on the upstream side, join at a combining portion 62 b on thedownstream side. The branching channels 62A and 62B includes theejectors 21 respectively.

The branching portion 62 a is provided with a changeover valve 62 c sothat the combustion exhaust gas G is capable of being selectively blowninto only one of the branching channels 62A and 62B.

According to the above configuration, since the bypass channel 62 hasthe branching channels 62A and 62B, and the ejector 21 is provided ateach of the branching channels 62A and 62B, it is possible to circulatethe combustion exhaust gas G using one of the branching channels 62A and62B (for example, the branching channel 62A) and to clean the ejector inthe other (for example, the branching channel 62B). Therefore, theadhered substance F on the inner wall surface 21 a of the ejector 21 canbe removed by cleaning the ejector 21 while continuing the operation ofthe melting equipment 1D.

It is needless to say that three or more branching channels may beprovided.

Fifth Embodiment

FIG. 12 is a schematic configuration view showing melting equipment 1Eaccording to a fifth embodiment of the invention. In FIG. 12, the sameconfiguration components as in FIGS. 1 to 11 will be given the samereference signs, and description thereof will not be made.

As shown in FIG. 12, the melting equipment 1E includes anadhesion-prevention unit 38. The adhesion-prevention unit 38 includes afume cleaning tower (liquid dispersion portion) 70 that removes theincorporated substance included in the combustion exhaust gas G bysprinkling water to the combustion exhaust gas G, at the upstream of theejector 21.

The fume cleaning tower 70 includes a casing 71; a pump 72 thatsprinkles water that is stored at the bottom portion of the casing 71from the top portion of the casing 71; a filler layer 73 that is formedin, for example, a ring shape so as to receive sprinkled water, andholds water on the surface so as to promote gas-liquid contact, and ademister 74 that is provided at an outlet of the casing 71.

The ejector 21 is configured to be driven using the high-pressure air Ahaving a temperature that is equal to or higher than the melting point.

According to the above configuration, since the fume cleaning tower 70is included upstream of the ejector 21, the incorporated substance thatreaches the contraction portion 23 of the ejector 21 is capable of beingreduced. Thereby, it is possible to reduce the adhered substance F beingattached to the contraction portion 23 of the ejector 21.

In addition, since the demister 74 arranged at the outlet of the casing71 is provided, it is possible to prevent misty water from flowing intothe ejector 21 and the bypass channel 20 on the downstream side.Furthermore, since the high-pressure air A in the ejector 21 is at themelting point or higher, even when misty water is included in thecombustion exhaust gas G due to water sprinkling, it is possible toprevent a water from attaching on the inner wall surface 21 a in theejector 21 and the wall surface of the bypass channel 20 by vaporizingthe moisture. Thereby, since the residual incorporated substance in thecombustion exhaust gas G is prevented from being trapped by waterattached on the inner wall surface 21 a of the ejector 21 and the wallsurface of the bypass channel 20, and therefore the combustion exhaustgas G is capable of being stably circulated by preventing the cloggingor narrowing of the combustion exhaust gas G channel.

The operation sequences, the shapes, combination, and the like of therespective component members as shown in the embodiments described aboveare an example, and various modifications are permitted based on designrequirements within the scope of the invention.

INDUSTRIAL APPLICABILITY

According to the melting equipment according to the invention, it ispossible to stably circulate combustion exhaust gas by suppressingclogging or narrowing of the channel of combustion exhaust gas.

DESCRIPTION OF THE REFERENCED SYMBOLS

-   -   1A, 1B, 1B1, 1B2, 1D, 1E MELTING EQUIPMENT    -   2 SWIRLING MELTING FURNACE (MELTING FURNACE)    -   7 SLAG EXTRACTION CHUTE    -   8 SECONDARY COMBUSTION CHAMBER    -   20 BYPASS CHANNEL    -   21 (21A, 21B), 26 TO 28 EJECTOR    -   21 a INNER WALL SURFACE    -   22 x SWIRLING SEPARATION CYLINDER (SWIRLING SEPARATION PORTION)    -   23 CONTRACTION PORTION    -   25 DRIVING AIR SUPPLY PIPE    -   31 TO 36, 36A, 37, 38 ADHESION-PREVENTION UNIT    -   41 AIR KNOCKER (ADHERED SUBSTANCE REMOVAL PORTION)    -   42 AIR BLUSTER (ADHERED SUBSTANCE REMOVAL PORTION)    -   43 WASHING BRUSH (ADHERED SUBSTANCE REMOVAL PORTION)    -   44 CYCLONE SEPARATOR(SWIRLING SEPARATION PORTION)    -   44 a INNER WALL    -   44 b COOLING SYSTEM    -   45 AIR SUPPLY PIPE (AIR FILM FORMING PIPE)    -   46 DRIVING AIR SUPPLY PIPE (AIR FILM FORMING PIPE)    -   62 BYPASS CHANNEL    -   62A, 62B BRANCHING CHANNEL    -   70 FUME CLEANING TOWER (LIQUID DISPERSION PORTION)    -   A HIGH-PRESSURE AIR    -   F ADHERED SUBSTANCE    -   G COMBUSTION EXHAUST GAS    -   S AIR (AIR FILM)

1. A melting equipment comprising: a melting furnace that combusts andmelts an ash; a secondary combustion chamber disposed above the meltingfurnace; a slag extraction chute that guides a slag generated in themelting furnace downward; a bypass channel that connects the slagextraction chute and the secondary combustion chamber; an ejector thatis provided on the bypass channel, has a contraction portion at which achannel cross section thereof is narrowed, and suctions a combustionexhaust gas into the bypass channel; and an adhesion-prevention unitthat prevents an incorporated substance that is incorporated in thecombustion exhaust gas from attaching to an inner wall surface of theejector.
 2. The melting equipment according to claim 1, wherein theadhesion-prevention unit has an adhered substance removal portion thatremoves an adhered substance that is attached to the inner wall surfaceof the ejector.
 3. The melting equipment according to claim 2, whereinthe adhered substance removal portion supplies vibration to the innerwall surface of the ejector.
 4. The melting equipment according to claim2, wherein the adhered substance removal portion blows an air to theinner wall surface of the ejector.
 5. The melting equipment according toclaim 2, wherein the adhered substance removal portion performsmechanical washing on the inner wall surface of the ejector.
 6. Themelting equipment according to claim 1, wherein the adhesion-preventionunit has a swirling separation portion that is provided at an upstreamof the contraction portion, swirls the introduced combustion exhaust gasso as to form a swirling flow, and centrifugally separates anincorporated substance included in the swirling flow.
 7. The meltingequipment according to claim 6, wherein the swirling separation portionhas a cooling system that cools the inner wall along which the swirlingflow of the combustion exhaust gas flows.
 8. The melting equipmentaccording to claim 6, wherein a plurality of the ejectors is provided ina row.
 9. The melting equipment according to claim 1, wherein theadhesion-prevention unit has an air film forming portion that forms anair film along the inner wall surface of the ejector.
 10. The meltingequipment according to claim 1, wherein: the adhesion-prevention unitincludes a plurality of replaceable branching channels that is providedat the bypass channel, and branches on the upstream side and joins withthe downstream side; and each of the plurality of the branching channelshas an ejector.
 11. The melting equipment according to claim 1, wherein:the adhesion-prevention unit includes a liquid dispersion portion thatis provided upstream of the ejector, and disperses liquid in thecombustion exhaust gas so as to remove the incorporated substanceincluded in the combustion exhaust gas; and the driving air in theejector has a temperature that is equal to or higher than thetemperature at which the dispersed liquid gasifies.